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F Dufour

Publications and source records attributed to F Dufour.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance.

A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.

Journal Article↗
PubMed2006

Trans-metastasis hepatectomy: results of a 21-case study.

AIM: The aim of this study was to report the feasibility and efficiency of a new approach, called post-RF trans-metastasis hepatectomy (PRFTMH). This technique consists in using RF to first ablate an ill-located liver metastasis (LM) along the planned hepatectomy resection line, the only one possible for volumetric reasons, and then to perform the hepatectomy passing via this initially ablated LM. MATERIAL AND METHODS: Twenty-one patients were treated with PRFTMH between January 2000 and May 2004. Thirteen of them had a primary colorectal tumour, four had a primary endocrine tumour and four had miscellaneous primaries. The mean number of LMs per patient was 13.8 (10.7 for primary colorectal tumours and 22.2 for primary endocrine tumours). Pre-operative hypertrophy of the future remaining liver was obtained by selective portal vein embolisation in 11 patients. RESULTS: One patient died post-operatively (4.7%) and five developed complications (24%). No local recurrence has occurred at the site of PRFTMH after a median follow-up of 19.4 months (range: 47-7), demonstrating the efficacy of this technique. All patients, except the patient who died post-operatively, are currently alive, and the median survival rate has not yet been attained, after a median follow-up of 19.4 months. CONCLUSION: PRFTMH combining RF ablation and trans-metastasis hepatectomy is a new and safe technique, allowing a curative approach to be proposed to some patients with unresectable bilateral LMs.

Adult↗
PubMed2001

Metabolic approach of absence seizures in a genetic model of absence epilepsy, the GAERS: study of the leucine-glutamate cycle.

We suggest that a dysregulation of energy metabolism in the brain of genetic absence epilepsy rats from Strasbourg (GAERS) could create a specific cerebral environment that would favor the expression of spike-and-wave discharges (SWD) in the thalamocortical loop, largely dependent on glutamatergic and gamma-aminobutyric acid (GABA)-ergic neurotransmissions. We tested several aspects of metabolic activity in the brain of GAERS compared to a genetic strain of nonepileptic (NE) rats. Glucose metabolism was higher in all brain regions of GAERS compared to those of NE rats along the whole glycolytic and aerobic pathways, as assessed by regional histochemical measurement of lactate dehydrogenase and cytochrome oxidase activities. Branched-chain amino acids (BCAA) and alpha-ketoisocaproate (alpha-KIC), the ketoacid of leucine, when injected intraperitoneally, increased the number of SWD in GAERS but had only a slight effect on their duration. These data speak in favor of a BCAA- or alpha-KIC-induced change in neuronal excitability. Leucine and alpha-KIC decreased the concentration of glutamate in thalamus and cortex without affecting GABA concentrations. Thus, BCAA and alpha-KIC, by decreasing glutamatergic neurotransmission, could favor GABAergic neurotransmission, which is known to increase the occurrence of seizures in GAERS. Finally, the transport of [1-(14)C]alpha-KIC in freshly isolated cortical neurons was lower in GAERS than in NE rats, and this difference was shown to be of metabolic origin. The addition of gabapentin, a specific inhibitor of BCAA transaminase (BCAT), reduced the transport of [1-(14)C]alpha-KIC in GAERS and NE rats to a level that became identical in both strains. This strain-dependent change was not related to a difference in the activity of BCAT, which was identical in GAERS and NE rats. The exact origin of this apparent metabolic dysregulation of energy metabolism in GAERS that could underlie the origin of seizures in that strain remains to be explored further.

Acetates↗
PubMed2001

Modulation of absence seizures by branched-chain amino acids: correlation with brain amino acid concentrations.

The occurrence of absence seizures might be due to a disturbance of the balance between excitatory and inhibitory neurotransmissions in the thalamo-cortical loop. In this study, we explored the consequences of buffering the glutamate content of brain cells on the occurrence and duration of seizures in Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a genetic model of generalized non-convulsive epilepsy. Branched-chain amino acids (BCAAs) and alpha-ketoisocaproate (alpha-KIC), the ketoacid of leucine were repeatedly shown to have a critical role in brain glutamate metabolism. Thus, GAERS were injected by intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) route with these compounds, then the effects on seizures were evaluated on the electroencephalographic recording. We also measured the concentration of amino acids in thalamus and cortex after an i.p. injection of leucine or alpha-KIC. Intracerebroventricular injections of leucine or alpha-KIC did not influence the occurrence of seizures, possibly because the substances reached only the cortex. BCAAs and alpha-KIC, injected intraperitoneally, increased the number of seizures whereas they had only a slight effect on their duration. Leucine and alpha-KIC decreased the concentration of glutamate in thalamus and cortex without affecting GABA concentrations. Thus, BCAAs and alpha-KIC, by decreasing the effects of glutamatergic neurotransmission could facilitate those of GABAergic neurotransmission, which is known to increase the occurrence of seizures in GAERS.

Action Potentials↗
PubMed1999

Modulation of pentylenetetrazol-induced seizure activity by branched-chain amino acids and alpha-ketoisocaproate.

Branched-chain amino acids, and mainly leucine act as nitrogen donors in the cerebral glutamate-glutamine cycle, thereby reducing brain excitability. Rats equipped with cortical electrodes received 300 mg/kg of leucine, isoleucine, valine or the ketoacid of leucine, alpha-ketoisocaproate at 2 h before the induction of seizures by 40 mg/kg pentylenetetrazol. Control groups received saline or a commercial mixture of amino acids, Vamine(R). Leucine and isoleucine increased the latency to absence-like and tonic-clonic seizures but did not influence the duration of the tonic-clonic seizure. Vamine(R), valine and alpha-ketoisocaproate had no effect. These data are consistent with the role of leucine in buffering brain glutamate concentration.

Amino Acids, Branched-Chain↗
PubMed1997

Increased cathepsin D level in the serum of patients with metastatic breast carcinoma detected with a specific pro-cathepsin D immunoassay.

BACKGROUND: An increased cathepsin D (cath-D) level in breast carcinoma cytosol has been proposed as a prognostic parameter. However, no increase had been previously detected in serum when assaying total cath-D concentration. METHODS: The authors compared 2 radioimmunoassays of total cath-D and pro-cath-D in the serum of 3 groups of patients: those with metastatic breast carcinomas (n = 30), those with nonmetastatic breast carcinomas (n = 24), and healthy women (n = 21). RESULTS: There was a significant increase of total cath-D and pro-cath-D in the serum of 18 of the 30 patients with metastatic breast carcinoma. No increase was observed in any of the patients with nonmetastatic disease compared with healthy women. Moreover, the level of pro-cath-D was often superior to that of total cath-D in the same patients, suggesting that the total cath-D assay in serum underestimates the actual concentration of pro-cath-D. This is not believed to be due to the masking of cath-D with the circulating mannose-6-phosphate/insulin-like growth factor II receptor because the purified receptor did not interfere in the binding of the monoclonal antibodies used in the assay to cath-D. CONCLUSIONS: An increased level of cath-D in the serum of breast carcinoma patients is a late event observed only in patients with metastatic disease. This increased circulating level is more likely due to increased secretion of the proenzyme rather than to tumor cell lysis.

Adult↗
PubMed1996

Isolation of 10 differentially expressed cDNAs in p53-induced apoptosis: activation of the vertebrate homologue of the drosophila seven in absentia gene.

We report the isolation of 10 differentially expressed cDNAs in the process of apoptosis induced by the p53 tamor suppressor. As a global analytical method, we performed a differential display of mRNA between mouse M1 myeloid leukemia cells and derived clone LTR6 cells, which contain a stably transfected temperature-sensitive mutant of p53. At 32 degrees C wild-type p53 function is activated in LTR6 cells, resulting in programmed cell death. Eight genes are activated (TSAP; tumor suppressor activated pathway), and two are inhibited (TSIP, tumor suppressor inhibited pathway) in their expression. None of the 10 sequences has hitherto been recognized as part of the p53 signaling pathway. Three TSAPs are homologous to known genes. TSAP1 corresponds to phospholipase C beta 4. TSAP2 has a conserved domain homologous to a multiple endocrine neoplasia I (ZFM1) candidate gene. TSAP3 is the mouse homologue of the Drosophila seven in absentia gene. These data provide novel molecules involved in the pathway of wild-type p53 activation. They establish a functional link between a homologue of a conserved developmental Drosophila gene and signal transduction in tumor suppression leading to programmed cell death.

Animals↗
PubMed1995

[Cellular senescence and survival of T lymphocytes].

In order to study cellular senescence in T lymphocytes and its link with aging, we have undertaken long-term cultures from adult individuals (aged from 20 to 40) and centenarians. The proliferative advantage of CD4+ over CD8+ T cells is reversed after the second stimulation. Periodically stimulated cultures remained exponentially growing during nearly 200 days, whereas 2 of them that were continued for 300 days stopped proliferating. However, once this phase of senescence is reached, the cells do not die out. Six other cultures remained viable for 34 months without proliferation but with conservation of the cell number. Three of these cultures have clonal karyotypic abnormalities: trisomy 2 and telomeric fusions.

Adult↗
PubMed1992

Increased synthesis of extracellular spleen glycosaminoglycans in an experimental myeloproliferative syndrome.

The changes occurring in the hematopoietic extracellular matrix in an experimental myeloproliferative syndrome were explored by comparing the glycosaminoglycan (GAG) composition of normal mouse spleens and spleens infected with myeloproliferative sarcoma virus (MPSV). Large quantities of hyaluronate and of sulfated GAGs accumulated in the extracellular matrix of infected spleens, as shown by histoimmunoassay and alcian blue staining, respectively. The splenic GAGs were either labeled with 35S-sulfate injected in vivo or unlabeled. The spleens were fractionated to separate hematopoietic cells from the stromal component containing extracellular matrix material and fibroblasts, and the GAGs were extracted from each fraction. Specific degradative treatments and electrophoresis indicated that sulfated GAGs were mostly chondroitin sulfate and heparan sulfate. Three hours after in vivo injection of 35S-sulfate, the amount of 35S-GAGs was increased approximately fivefold per mg stromal proteins. The bulk of these 35S-GAGs (70%) was recovered in the stromal fraction. The higher amount of sulfated GAGs in leukemic spleen was due both to the presence of more producer cells (infected fibroblasts and hematopoietic cells) and to a stimulation of GAG synthesis per cell, as evidenced 35S-labeling in in vitro experiments. Chondroitin sulfate was the main sulfated GAG present in the culture medium of both hematopoietic and fibroblastic cells and in the pericellular material released by trypsin from fibroblastic cells. High amounts of chondroitin sulfate, which has a possible role in the detachment of hematopoietic cells from the stromal cells, may favour the release of hematopoietic cells from the spleen into the peripheral blood. Heparan sulfate was produced by fibroblastic cells and it was principally present in their pericellular material. Considering the capacity of heparan sulfate to retain cytokines, as demonstrated by others in vitro, large amounts of heparan sulfate may result in the retention of large amounts of the cytokines, which production is enhanced in the infected spleen. This phenomenon may contribute to promote the hematopoietic stem cell proliferation characteristic of the MPSV-induced myeloproliferative disease.

Animals↗
PubMed1985

[Our experience in the serodetection of Chlamydia infections in tubal pathology].

Chlamydia appears to be an increasingly frequent cause of salpingitis and its complications (sterility, extra-uterine pregnancy). The difficulty of isolating Chlamydia in cell cultures has led us to study the value of serology in the form of immunofluorescence and ELISA. This study is based on 475 cases (206 controls and 269 women with tubal disease). Although it is difficult to interpret an isolated IgG level, the results nevertheless confirmed the value of serodetection: especially the comparison between the control group (18.44% positive) and the pathological group (62.08% positive) and the effectiveness obtained when cases of tubal sterility were treated with appropriate antibiotics, alone or in combination with surgery.

Animals↗
PubMed1984

[Physiopathology of pregnancy-induced hypertension].

Even though multiple factors are involved in arterial blood pressure elevation, during pregnancy-induced hypertension normal physiologic processes are occurring in the uteroplacental unit. These appear probably very early in pregnancy. Treatment of pregnancy-induced hypertension at the present time is directed simply at lowering the blood pressure. It should be emphasized that only one placebo-controlled study has demonstrated a beneficial effect of antihypertensive treatment for the fetus in moderate pregnancy-induced hypertension. Future treatment very likely will be preventive, administered from the onset of pregnancy in a high-risk patient.

Catecholamines↗